Long-term (≥15 years) effects of Class II treatment: a longitudinal and cross-sectional study on signs and symptoms of temporomandibular disorders

Background: The aetiology of temporomandibular disorders (TMD) is controversial and post-orthodontic long-term TMD data of Class II populations are scarce.

Objectives: To analyse the long-term (≥15 years) effects of Herbst-multibracket appliances (MBA) Class II treatment (Tx) on signs and symptoms of TMD.

Subjects and methods: All patients (University of Giessen, Germany) who underwent Herbst-MBA Tx (end of active Tx ≥ 15 years ago), could be located and agreed to participate in a recall. Available records from before (T0) and after (T1) active Tx were used for comparison with the recall data (T2). All findings were classified according to research diagnostic criteria for temporomandibular disorders (RDC/TMD) and diagnostic criteria for temporomandibular disorders (DC/TMD) as well as the Helkimo index.

Results: Seventy-two out of 152 patients participated at age 33.7 ± 3.0 years. Complete TMD data-sets (T0 + T1 + T2) were available for 33 participants. Participants and non-participants did not differ significantly at T0 or T1 in terms of general clinical data, occlusal relationship or TMD prevalence. At all time-points, 79-91 per cent of the patients were free of TMD signs and symptoms (RDC/TMD and DC/TMD). The TMD prevalence fluctuated: 21 per cent (T0), 9 per cent (T1), 15 per cent (T2). Similar findings with a trend towards improvement during T0-T1 and recurrence during T1-T2 were seen for the Helkimo index. There were no statistically significant differences.

Limitations: The participation rate of only 62 per cent, the disparate availability of records (T0, T1), the fact that the patients were not treated at exactly the same time period and that no untreated control group is available.

Conclusion: In the long-term (≥15 years) Herbst-MBA Class II Tx neither seems to increase nor decrease the risk for developing TMD.